Dr Sodha has made important theoretical contribution in the broad area of interaction of fields with matter. His work on self-focussing in plasmas is significant with possible important applications in laser fusion. Following a new approach, he has obtained interesting results on self-focussing in optical fibres which will be useful for optical communication. He has made important theoretical contributions in the field of harmonic generation in plasmas and semiconductors. His work on plasmas has a bearing on magneto-hydrodynamic (MHD) power generation.